I've been waiting anxiously for Dead Space 2 to come out (I loved the first one enough to watch the related anime movie and read the related graphic novel), and I just couldn't take it any longer.  I needed to get my horror-in-space fix, so I loaded up Doom 3 to try to play through it for the first time.  As a gamer, I grew up on Doom; I played Doom, Doom II, and Quake all through high school, and Quake II and Quake III in college.  I was a big fan of id Software, they always seemed light years ahead of other FPS games at the time (especially when you compared them to console FPS games).  Id games were the reason I could never get into Goldeneye.  Why would I ever play that when Quake III is so much better? 
 
Anyway, I got it recently on sale from Steam (I think $5 or so), and it's definitely been worth it.  But I've been pretty surprised with what I've liked and what I haven't liked so far.  I've liked the story (which is funny, because as far as I know, past Dooms and Quakes basically didn't have plots).  The voice acting is also done reasonably well.  But the visuals and the combat are pretty so-so. The graphics haven't aged well for a game that isn't really that old (it came out in late 2004).  And the combat feels pretty similar to past Doom games.  There's no cover system, bullet time, or anything else more advanced like that.  In that regard, it doesn't really measure up favorably against, say, F.E.A.R.  But, like in the old Doom games, the level designers can be proud of the various "jump" moments throughout the game, both in terms of quality and quantity.  I haven't seen another game as good at making me react at something popping out behind me.  So good job on that.  

I've been waiting anxiously for Dead Space 2 to come out (I loved the first one enough to watch the related anime movie and read the related graphic novel), and I just couldn't take it any longer.  I needed to get my horror-in-space fix, so I loaded up Doom 3 to try to play through it for the first time.  As a gamer, I grew up on Doom; I played Doom, Doom II, and Quake all through high school, and Quake II and Quake III in college.  I was a big fan of id Software, they always seemed light years ahead of other FPS games at the time (especially when you compared them to console FPS games).  Id games were the reason I could never get into Goldeneye.  Why would I ever play that when Quake III is so much better? 
 
Anyway, I got it recently on sale from Steam (I think $5 or so), and it's definitely been worth it.  But I've been pretty surprised with what I've liked and what I haven't liked so far.  I've liked the story (which is funny, because as far as I know, past Dooms and Quakes basically didn't have plots).  The voice acting is also done reasonably well.  But the visuals and the combat are pretty so-so. The graphics haven't aged well for a game that isn't really that old (it came out in late 2004).  And the combat feels pretty similar to past Doom games.  There's no cover system, bullet time, or anything else more advanced like that.  In that regard, it doesn't really measure up favorably against, say, F.E.A.R.  But, like in the old Doom games, the level designers can be proud of the various "jump" moments throughout the game, both in terms of quality and quantity.  I haven't seen another game as good at making me react at something popping out behind me.  So good job on that.  

To me, the lack of cover or bullet time or a fingerless glove meter has always been part of the appeal of Doom. I still go back and play the first two because they're just fun. Sometimes, I don't want a fancy story or gimmicky game mechanics; I just want to switch my brain off and blast demons with a shotgun.

Yeah, the linear combat approach in Doom 3 is its main letdown...
Kinda unrelated: have you tried Prey? Not really survival horror, but it uses the same engine as Doom 3 and has some much more interesting gameplay mechanics, in my opinion. An overall superior game and a real "unknown" FPS gem :)

I loved Doom 3. To this day I still don't understand the hate it got. Graphics were great in it's day, shooting felt good, lots of good jump scares, and sweet interactive screens.

 
I really enjoyed Doom 3, still play it occasionally  
 
it was jumps scares and stuff but it was great all the same, i had never played a doom game before but i bought the limited edition one for xbox and it came with them so i got to experience those and they're great games too, as @Artemesia says, they're just fun 
   
started it again recently actually and forgot how atmospheric it was, even the earlier levels just walking around the base

Man, Doom 3 is such an awesome fucking game. I've played through it at least eight or nine times, and I played through Resurrection Of Evil at least two or three times. I just love the atmosphere, the music, and the general attitude.

Doom 3 was good but  to me the worst part of it was that the enemies would spawn in front of you and right behind you in nearly every encounter and it became very predictable.

" @KillyDarko: Never played the full version of Prey, although I think I might have experimented with a demo at one point.  It looked like a fairly run-of-the-mill shooter at the time, and the backstory that I read about didn't do much for me, but I have heard some good things about it since then.  Is it still worth picking up? "

Yep, this game gets lots of unwarranted hate. I loved it.
 
And yes, you should pick up Prey too.

" Doom 3 was good but  to me the worst part of it was that the enemies would spawn in front of you and right behind you in nearly every encounter and it became very predictable. "

Remember, there are duct tape mods out there.

I have such fond memories of Doom 3. This and Riddick were my two favorite shooters on the original Xbox. I'm surprised at how well the graphics hold up to this day.